Reheating continuous furnace hearth



E. D; WRIGHT REHEATING CONTINUOUS FUENACE HEARTH June 19, 1928. 1,674,147

Filed NOV. 1925 3 Sheets-Sheet 1 E. D. WRIGHT REHEATING CONTINUOUS FURNACE HEARTH June 19, 1928.

Filed Nov. 6, 1926 5 Sheets-Sheet 2 M m a June 19, 1928.

E. D. WRIGHT REHEATING CONTINUOUS FURNACE HEARTH Filed Nov, 1926 3 Sheets-Sheet 3 cyfiver7%r Patented June 19, 1928.

UNITED STATES m1. 1). main, or sown cnrcaeo, rumors.

BEHEATIHG CONTINUOUS FURNACE HEABTH,

Application filed November 8, 1928. Serial No. 146,869.

My invention relates to a furnace hearth for use in continuous reheating furnaces used in the reheating of steel billets prior to the rolling thereof into shapes and as particular reference to a hearth construction in which the temperatureof the billets is maintained as evenly as possible throughout the entire billet, even though it is supported on the hearth during a art of the time required for the reheating o the billet.

A further object. of my invention-1s the provision of a hearth having a billet d1scharge arrangement associated therewith so that the heated billets as they are discharged from the furnace have their temperature maintained and are uniformly heated throughout before being discharged from the furnace.

Another and further object of my mvention is the rovision of a furnacehearth of smooth and continuous construction over which steel billets can be passedwithout 1nterrupting the passage of the billets or unnecessarily lowering the tem erature of the billets as they pass over the earth.

In continuous reheating furnaces it has been the practice to chargethe furnace at one side thereof with the billets and to push the billets across skids arranged 1n long ltudinal relation with the furnace and in spaced parallel relation with each other, t rough which water is ke t continuously flowin in order that the skids may not be burne out of the furnace, these skids forming supporting members for the billets as they pass through a large part of the furnace. The skids beings in contact with the billets prevent the billets on the side thereof WhlCh rests upon the skid from being heated to the same degree as other parts 0 the billet, with the result that a certain area of each billet which is in contact with the skid. is not heated to the same temperature as' the balance of the billet. The practice is to'push the billets onto a hearth provided in the furnace for the purpose ofenabling the entire billet to become unifofimly heated before it is discharged from the eatin nace. These hearths have been made 0 ma nesite brick which in time become misplaced, presenting a rough and, uneven surface over which the billets must pass retarding their passage and taking the heat therefrom. It is the usual ractice to provlde a trough at one side of he hearth, usually water-cooled,

for the purpose of receiving the billets and furfrom which the billets are discharged by a pusher apparatus directly intothe roll pass, but this practice is objectionable because the temperature of the billet is reduced too much.

The billets cannot be discharged directly from the hearth because the friction .of the billet passing over the surface of the hearth would soon wear the hearth to such a de ee. that the operation of the furnace woul be interrupted until it could be repaired.

In my improved construction, these difficulties are overcome and means are provided comprising a pair of steel billets embedded in a sandstone hearth placed in spaced relation parallel with each other, upon which the billets rest as they are discharged from the furnace, these billets of course, being heated and the billets resting thereon will be of substantially the same heat as the billets comprising the discharge means, so that when a billet is discharged fromthe heating furnace it is substantially uniformly heated throughout. The cooler areas formed by the contact of the billets upon the water-cooled skids have become heated, which is necessary because if these areas are not heated the rolling operation cannot be successfully performed. It is, of course, well known that cold steel under roll pressure expands laterally, while hot steel is elongated by the pressure of the rolls and therefore, unless these billets are substantially uniform when they enter the'rolls, ir-

regular shapes will be turned out from the rolls.

These and other ob'ects of my invention will be more fully an better understood by reference to the accompanying sheets of drawings in which Figure 1 is a longitudinal, vertical sectional 'view of a heating furnace equipped with my improved invention;

Figure 2 is a top plan view of the hearth of the heating furnace;

Figure 3 is a vertical sectional view illustrating the discharge means provided in the furnace hearth; and

Figure 4 is .a detailed view in perspectiveshowing the manner of securing the discharge members onto the furnace hearth.

Referring now specifically to the draw ings, aheatin furnace is shown having the usual foundations 10, with end walls 11 and of the furnace, and also to support a roof 1% which is the usual curved suspended form. A gas inlet is provided with an air passage 16 also being provided, through which air enters the furnace and becomes mixed with the gas entering through the passage 15 and passes up over ,a bridge wall 17 extending transversely across the furnace adjacent the discharge end of the furnace and over which the flames pass toward the receiving end of the heating furnace as the air and gas are consumed by the combustion thereof in the furnace. A receiving opening 18 is provided at one end of the furnace through which the billets are charged into the heating furnace, with a plurality of spaced skids 19 extending longitudinall of the furnace and having their outer en s curved downward beyond the outer wall of the furnace and their inner ends terminating adjacent the hearth of the furnace and turning downward into a water discharge pipe 20, these pipes or skids having water constantly flowing therethrough in order to preserve the skids, which form supports upon which the billets rest as they are forced through the furnace.

A hearth 21 is provided which is supported by a plurality of transversely extending eyebeams 22, 22, the said hearth extending from a point adjacent the termination of the skids 19, 19 to the lower side of the bridge wall 17. The hearth in my improved construction is made up of a plurality of rectangular shaped sandstone slabs 23, 23 and 23, 23, placed in two sets, each set being placed in end to end relation with each other, the slabs in each set being in edge to edge relation with each other, this hearth being heated and receiving the billets as they are forced from the skids 19 through the heating furnace, and is provided for the purpose of enabling the billets to become uniformly heated after they ass over the water-cooled skids 19, 19. A ischarge door 24 is provided at one side of the furnace through which the billets are discharged from the heating furnace b pusher, not shown, and whic is in common use in heatin furnaces of this type, the discharge door ieing at the end of a runway formed by a pair of skids 25 and 26, these skids being formed of steel billets having their upper surface curved and extending above the level of the hearth 21 for a slight distance and adapted to receive the billets as they are forced through the heating furnace and over which the billets are discharged by the combined action of the pusher and the rolls.

The skid 25 is supported by a plurality of vertically extending osts 27, 27, these posts being s aced a suite. 1e distance to support the ski 25, referably with a post at each end of the s id and for the ordinary type a mechanical.

of heating furnace with an intermediate post placed half way between the two end posts, although this arrangement may be altered if desired. The skid 26 is also supported by a plurality of posts 28, 28, these posts being placed in spaced relation with each other and opposite the posts 27, 27 supporting the skid 25 so that the skid 2G is supported upon these posts and a spaced runway is formed over which the billets are discharged through the discharge door 2f in the side of the furnace. One of the posts 28 is illustrated in detail in Figure 4 and comprises a rectangular shaped billet having a V-shaped recess 2!) in the upper end thereof with a hole 30 extending through one side of the post through which a bolt 31 extends. The bolt 31 has a feather-key 32 in a keyway 33 formed in the lower end of the bolt 31, the skid 26 also having a diagonally extending hole 34 therethrough in register with the hole 30 in the post 28, with a countor-sunk recess 35 in the upper side thereof within which the head of the bolt 31 is adapted to seat. The lower end of the posts 28 has a rod 36 extending transversely therethrough with eyebolts 37 and 38 secured to the bolt 36 and extending through the supporting plate at the bottom of the hearth with ordinary nuts on the ends of the eyebolts so that the posts 28 can be drawn down tightly in position and supported by the bottom plate of the hearth. Each of these posts 28 is constructed in the manner heretofore described and the posts 27 are also constructed in precisely the same manner, except that the holes through the skid 25 extend in an outward direction with bolts passing through the members 25 and feather-keys in the outer side thereof in precisely the same manner except that they extend in directions opposite to the bolts 31. It will be understood, of course, that these skids 25 and 26 become heated to substantially the same temperature as the billets and that as these skids become heated they expand and the expansion draws the structure together very tightly, and that the structure also yields in a plurality of places when cooled. due to a slight relative movement of the skids and posts and the eyebolts. so that while a slight amount of expansion and contraction is permissible when the device is heated, the entire structure expands so that it practically becomes a unitary structure.

Should the skids 25 and 26 become worn they can easily be removed and replaced with new skids without an unusual delay in the operation of the furnace or without tearing down the structure of the furnace in order to replace the skids. V-shaped recesses are also formed in the hearth blocks 23, 23 adapted to receive the skids 25 and 26 so that, as heretofore explained, these skids fit into the hearth transversely thereof with their curved upper surfaces extended a slightdistance above the surface of the hearth and forming skids or a runway over which the billets are discharged from the furnace.

In the operation of the device it will be understood that the billets are fed into the furnace through the opening 18 by means of a mechanical pusher, not shown, and which is in common use in the operation of these heating furnaces, these billets being fed into the furnacetransversely of the skids l9 and lying thereon during the initial heating thereof, it being understood that the billets are fed into the furnace-one at a time and the front billets pushed across the heating furnace in a step by stepoperation as other billets are fed into the furnace by the pusher, the pusher being timed so that the billetsare allowed to remain in the furnace a sufiici'ent length of time so that they are thoroughly heated and supplying the rolls with heated billets as rapidly as they can be taken out of the furnace by the rolls. The

line of billets extends across the skids where they adually become heated as they reach the hearth 21. The points of contact of the billets with the skids 19 will not be heated as high as other portions of these billets, for the reason that the skids are water-cooled and the temperature at these points is re duced so that as the billets pass upon the hearth, which is composed of sandstone and extends longitudinally of the furnace, these portions of the billets commonly known as black spots will be heated to the same deree asthe balance of the billet, so that as the billets pass across the hearth 21 the billet is uniformly heated throughout its entire structure. hese billets are pushed upon the discharge skids 25 and 26 formed of heavy steel billets, and are heated to su stantially the same temperature as the billets when they reach the'skids passing through the heating furnaces. When they reach these skids they are discharged from the heating furnace through the door 24 by a mechanical pusher into the first roll pass, the mechanical pusher being one in common use and not shown in connection with this application. The temperature of the billets on the under side may be slightly reduced from that of the upper side, but this is immaterial for the reason that the upper rolls in the roll pass are, usually water-cooled and .the'hot side of the billets will not stick to these rolls and as the billet enters the rolls the upper side coming-in contact with the water-cooled rolls will be reduced in teni-' erature so that as the billet enters the rolls its temperature is substantially uniform throughout and results in the same reentage of elongation be'ing maintained t roughout theentire billet without the rough spots being formed therein which have been com mon heretofore.

\Vhile I have described more or less precisely, the details of construction, I do not wish to be understood as limiting myself thereto, as I contemplate changes in form and the proportion of parts and the substitution of equivalents as circumstances may suggest or render expedient Without departing from the spirit or scope of my invention.

I claim:

1. A hearth for continuous heating furnaces comprising in combination a plurality of sandstone slabs and a pair of discharge skids extending. transversely of the said furnace, each of said skids having its edges rounded and extending a slight distance above the level of the heart-hs surface.

2. A discharge runway for a continuous heating furnace comprising in combination a pair of members in spaced longitudinal relation with each other extending transversely across the furnace hearth, a plurality of posts supporting the said members and means for securing said posts to the furnace.

3. A runway for heating furnaces comprising in combination a pair of members in spaced longitudinal relation with each other having their upper surfaces rounded and extending above the'surface of the hearth, a plurality of posts upon which said members are mounted, means for securing the said runway members to the said posts and means for securing the said posts to the said furnace.

4. A discharge runway for continuous heating furnaces comprising in combination. a pair of members in spaced relation with each other and extending transversely across the said hearth, a plurality of posts having V-shaped recesses in their upper ends adapt-' ed to support the said s aced members, means for securing the said posts to the said furnace, and meansfor securing the said runway members to the said posts, the

under surface of the said runway members fitting into the said V-shaped recesses of themeans for securing the said posts to the said furnace, means for securing the said runway members to the said posts, the under surface of the said runway members fittin into the said V-shaped recesses of the sai posts, bolts extending through the ends of said posts and through said skid members, and members in contact with the said posts.

keys adapted to hold the said skid 6. A discharge runway for a heating furnace comprisin a steel billet extending across the said urnace, the said billet having its upper edge rounded and extending below the furnace hearth and means for supporting the billet in the furnace hearth.

7. A discharge runway for heating furnaces, comprising a pair of steel billets in spaced relation with each other extending transversely of the said furnace, means for supporting the billets in the furnace hearth, the said billets having their upper edges rounded, the highest point of said billets extending above the furnace hearth and the edges of the rounded portions extending below the furnace hearth.

8. A continuous heating furnace comprising in combination, skids adapted to support billets, a sandstone hearth adapted to receive the billets when discharged from said supporting skids and discharge skids mounted in said heart the discharge skids being adapted to be heated to substantially the same temperature as the billets discharged thereover.

9. A continuous heating furnace comprising in combination, su porting skids, a sandstone hearth adapte to receive billets when discharged from said su porting skids, and steel billets forming a ischarge runway in said hearth, the said billets being heated to substantially the same temperature as the heated billets passing thereover.

Signed at Chicago, Illinois, this 29th day of October, 1926.

EARL D. WRIGHT. 

